Sub aux(n As Integer, i As Integer, a() As Integer, _
        u() As Integer, v() As Integer, ByRef m As LongInt)

    Dim As Integer j, k, p, q
    If i > n Then
        m += 1
        For k = 1 To n : Print a(k); : Next : Print
    Else
        For j = i To n
            k = a(j)
            p = i - k + n
            q = i + k - 1
            If u(p) And v(q) Then
                u(p) = 0 : v(q) = 0
                a(j) = a(i) : a(i) = k
                aux(n, i + 1, a(), u(), v(), m)
                u(p) = 1 : v(q) = 1
                a(i) = a(j) : a(j) = k
            End If
        Next
    End If
End Sub

Dim As Integer n, i
Dim m As LongInt = 1
If Command(1) <> "" Then
    n = CInt(Command(1))
    ReDim a(1 To n) As Integer
    ReDim u(1 To 2 * n - 1) As Integer
    ReDim v(1 To 2 * n - 1) As Integer
    For i = 1 To n
        a(i) = i
    Next
    For i = 1 To 2 * n - 1
        u(i) = 1
        v(i) = 1
    Next
    m = 0
    aux(n, 1, a(), u(), v(), m)
    Print m
End If